But having spent a little time reviewing Biden's primary run, I've been struck by how cautious Biden was in his statements. Biden talked constantly about the importance of experience--and the fact that he had the most of it. It was the centerpiece of his campaign. But, for the most part, he couched those arguments in general terms. He was usually comparing himself to the entire field of Democrats, not just one rival. And even on those occasions where he did talk about Obama, he did so with surprising nuance.

You know he’s a very smart guy. I can’t speak for me. But I know for me
that it was a learning experience. I worked very hard. I’m sure he’s
working very hard too. I’ve watched seven presidents, and I’ve watched
presidents who have come to office who haven’t thought through some of
the areas that theyt’ve never worked in, for example foreign policy. I
watched several presidents come in and they’re smart as the devil and
they get here and unless you already know when you get here exactly
what your foreign policy is, it’s awful hard to hit the ground running
and not to make serious mistakes the first couple of years. I’m not
saying that senator obama is where I was [when elected to the senate at
age 29]. I was younger than he was when he got to the Senate. But I do
think, I acknowledge that experience is not the issue, it’s whether
your experience has been good or bad. Somebody with 34 years of bad
experience isn’t perfectly qualified to be president, someone with 34
years of good experience that makes a big difference. So, again, I know
it’s kindo f difficult to master, it’s kind of difficult to feel
sure-footed in a lot of areas that you haven’t spent a long of time
dealing with.

As these sorts of quotes go, it's relatively mild. Biden doesn't actually say Obama lacks the experience to be president. In fact, he explicitly leaves open the possibility that Obama is ready for office.

I know of at least one more Biden quote along these lines, referenced here in this August, 2007 debate: "I think he can be ready, but
right now I don't believe he is. The presidency is not something that
lends itself to on-the-job training." Again, as campaign criticisms go, it isn't that awful. Biden can always say a lot has happened in the year since he said that. (He got to know Obama better, etc.)

Of course, there may be other, more damning statements out there. But if this is as bad as it gets--and if, again, Biden is the nominee--I don't think Biden's past rhetoric will pose much of a poiltical problem. (And, for the record, I don't think it should. Obama's lack of experience in foreign policy isn't ideal, but the judgment he's shown--combined with the intellect--makes me think he's up for the job. It seems perfectly reasonable to me that Biden has come to the same conclusion.)

Update: Just to clarify, it's obviously not a good thing that these quotes are out there. I'm just saying they could be much, much worse, given that Biden and Obama were rivals for the presidency just a few months ago.